Saying China's system works now and is successful is quite comparable to building a house on cheap land overtop of a recently-dropped unexploded bomb and saying it's a great idea and financial success because the bomb hasn't gone off yet. It says nothing about the long-term prospects of the strategy.
China is smack in the middle of a transition that's going to take over a century, and current prospects on economic outlook, energy consumption, and environmental damage, (not to mention civil unrest) are not particularly good if they don't alter course soon.
If their artificial undervaluation of their currency doesn't bite them square on the ass, their energy infrastructure will. If energy doesn't, the pollution will. If the pollution doesn't, the corruption will. And if the corruption doesn't, their contunous suppression of human rights and their citizenry will. China has a simmering pot of major issues underlying their economic "success" that aren't going away. The drive for economic success has come at the cost of many other aspects of daily life, and sooner or later they're going to have to pay that bill.